DomainKeys Identified Mail, or DKIM, is a method for checking the legitimacy of an email message by using a digital signature. When DomainKeys Identified Mail is activated for a particular domain, a public encryption key is published to the global DNS database and a private one is stored on the mail server. If a new email is sent, a signature is generated using the private key and when the email is received, that signature is authenticated by the POP3/IMAP server using the public key. In this way, the recipient can easily discern if the email is legitimate or if the sender’s address has been forged. A mismatch will appear if the content of the email message has been modified in the meantime as well, so DKIM can also be used to ensure that the sent and the received emails are identical and that nothing has been attached or removed. This validation system will strengthen your email security, as you can validate the genuineness of the important emails that you receive and your associates can do likewise with the emails that you send them. Depending on the given email service provider’s policy, a message that fails the test may be deleted or may show up in the receiver’s mailbox with a warning alert.